Research On The Influence Of Harmonic To The Metering Of Electric Energy

Electric power harmonic is one of the most important parameters. With the development of modern industry, high power electron devices are applied widely. Large harmonic and pollution brought into electric network. And electric energy measurement of electric force department and customer was influenced. So it is necessary that how to detect and measure harmonic electric energy.In this paper the effect of harmonic power on metering of electric energy is mainly discussed. The goal is to find a reasonable measurement way to electric utility and electric power users in harmonic condition.Firstly, through consulting a large number of domestic and foreign language materials,the structure of induction and electron type electric energy meter is introduced, and their operation principle is explained specially in detail. It points out the irrationality of electric energy measurement under current electric energy measuring standard through the expression formula of the electric energy consumed by linear loads and non-linear loads.Meanwhile, large quantities of simulation experiments have been carried on matlab/simulink platform, and the result shows that, induction type meter has a rather large inaccuracy on total power measure of fundamental wave and harmonic wave; while electronic type meter can accurately reflect the value being measured. However, both meters have contradiction between accuracy and rationality under current measuring manner.Secondly, it carries out harmonic analysis of the feed system of a steel plant, quantitatively researches the influence to linear loads related to one node when this node is being poured harmonics caused by non-linear load, and also the influence to harmonic contents of other nodes. Comparison between harmonic current allocate principle and simulation record shows the accuracy of simulation.Lastly, on the basis of current measuring manner, fundamental wave power and harmonic wave power were not calculated individually; then presents a toll scheme to modify user fees, implements penalty to non-linear loads and compensation to linear loads, meets the economical efficiency of power market.